Don't use If
Case ( Department = "Elementary" ; 500 ;
Department = "Middle School" ; 600 ;
Department = "High School" ; 700 )
But what happens when rates, costs etc change and you want to use a different amount for one or more of these values?
Instead of using a calculation where someone with developer skills has to redefine the calculation, set up a look up table of these departments and values so that your system can look up (copy) these values from the look up table and then changing the value becomes a data entry task rather than a developer task.